Marine vehicle with outboard propulsion unit hydrofoil exhaust



Oct. 12, 1965 MARINE VEHICLE WITH OUTBOARD PROPULSION UNIT HYDROFOIL EXHAUST Filed July 16, 1964 E. C. KIEKHAEFER 2 Sheets-Sheet 1 I m 1 J7 Q] INVENTOR.

[mile (4121. IGEKHAEFER Oct. 12, 1965 E. c. KIEKHAEFER MARINE VEHICLE WITH OUTBOARD PROPULSION UNIT .HYDROFOIL EXHAUST 2 Sheets-Sheet 2 Filed July 16, 1964 R O T m V m [ZMFR (41a A II/(HAEFER BY lffolvze 5 United States Patent Ofiice 3,2l l,l l9 Patented Get. 12, 1965 3,211,119 MARINE VEHICLE WITH OUTBOARD PRGPUL SION UNIT HYDRGFUIL EXHAUST Elmer Carl Kiekhaefer, Winter Haven, Fla., assignor to Kiekhaefer Corporation, Fond du Lac, Wis, a corporation of Delaware Filed July 16, 1964, Ser. No. 383,119 1 Claim. (Cl. 11466.5)

This invention relates generally to a marine vehicle, such as a boat, which is adapted for hydrofoil operation.

Boats so equipped have the advantage of substantially reduced drag, since at higher speeds the boat hull is lifted clear of the water so that only the hydrofoil, propeller and steering mechanism is beneath the surface,

In amine vehicles powered by one or more internal combustion engines, it is desirable to mufile or quiet the sound of exhaust gases being discharged from the engine. In accordance with the present invention, the exhaust sound is muffled by discharging it deep in the water. More particularly, the invention contemplates a hollow hydrofoil structure wherein the exhaust gases are passed therethrough and discharged below the boat hull.

Further in accordance with the invention, the boat is equipped with at least one hydrofoil mounted forwardly of the stern, and a further hydrofoil mounted rearwardly of the stern. A motor propulsion unit, such as an outboard motor, is mounted on the transom portion of the boat hull, and provides the rearward hydrofoil through which the exhaust gases are discharged.

The accompanying drawings illustrate the best mode presently contemplated by the inventor for carrying out the invention.

In the drawings:

FIGURE 1 is a side elevation of an outboard motorpowered boat and showing an embodiment of the invention;

FIG. 2 is an enlarged side elevation of the outboard motor connected to the boat, and with some parts broken away and shown schematically;

FIG. 3 is a vertical section of the boat taken on line 3-3 of FIGURE 1;

FIG. 4 is a rear end elevation of the lower portion of the motor, taken on line 4-4 of FIG. 2; and

FIG. 5 is a transverse section of the lower portion of the outboard motor taken on line 5-5 of FIG. 2, showing the position during straight run and during turn.

As shown in the drawings, the concept of the invention may be applied to a boat 1 of any suitable type adapted to ride in and above the water and adapted to be driven by an outboard propulsion unit in the form of an outboard motor 2 connected to the transom portion 3 of the boat hull. Boat 1 is designed to be lifted clear of the water during running speeds. For this purpose, at least two hydro-foils are provided, at least one forward of the boat stern and at least one rearwardly thereof.

The forward hydrofoil unit 4 comprises a pair of hydrofoil supports or struts 5 secured to the respective side-walls of the boat hull and which extend downwardly in a diverging manner to substantially below the hull. A generally wide V-shaped transversely extending hydrofoil 6 is secured to and extends between struts 5 beneath the hull. Hydrofoil 6 may be shaped in any suitable manner to provide the desired lifting action for the bow of the boat at running speeds. The center of the hydrofoil is generally disposed along a vertical plane containing the central longitudinal boat axis, and the entire unit 4 is rigidly fixed in relation to said axis.

The rear hydrofoil is provided directly in conjunction with outboard motor 2. For this purpose, motor 2 comprises an upper housing 7 containing an internal combustion engine 8 which is connected through suitable mechanism to drive shaft 9. Shaft 9 extends downwardly through a generally hollow drive shaft housing 10 and is connected through suitable mechanism at its lower end to drive an underwater propeller 11. An anti-cavitation plate 12 is disposed above propeller 11.

For purposes of the invention, the lower portion of shaft housing Ill is provided with a transversely extending wide V-shaped hydrofoil 13 which may be integral with the housing or secured thereon by any suitable means. Hydrofoil 13 is closely adjacent the position of anti-cavitation plate 12, and may be at the same level thereof so that they merge together. The hydrofoil 13 is above propeller 11 but is disposed sufficiently low on the outboard motor as to be below the boat hull bottom, for purposes to be described, and extends outwardly from housing 1t) substantially farther than the propeller blades.

When the boat is at running speeds, front hydrofoil unit 4 and rear hydrofoil 13 will cooperate to lift boat 1 clear of the water. The hydrofoils themselves and propeller 11 will normally remain submerged below the airwater interface. The lifting force of hydrofoil 13 will transmit upwardly through housing 10 and the usual horizontal tilt pin 14 to clamp bracket 15 and hence to the boat. Although hydrofoil 13 may provide resistance tending to cause motor 2 to tilt up rearwardly on pin 14, the forward thrust of propeller 11 will tend to overcome this.

Motor 2 is utilized to steer boat 1 by turning the motor about a vertically extending swivel pin 16. Thus in straight run, hydrofoil unit 4 and motor hydrofoil 13 will be parallel; while during turning hydrofoil 13 will be disposed at an angle to unit 4. Since hydrofoil 13 is below the bottom of the boat hull, it will pass therebeneath during turning.

In accordance with the invention, means are provided to discharge exhaust from engine 8 deeply under water. For this purpose, exhaust passing from the engine exhaust port 17 travels down through a conduit comprising housings 7 and ll) to adjacent hydrofoil 13. The latter is provided with a passageway 18 in one or both sections thereof, with the passageway connecting through rearward facing openings 19 in the hydrofoil wall to the surrounding Water. Thus the exhaust gases will be dis charged through openings 19 and beneath the water surface. Since the trailing edge of hydrofoil 13 forms a low pressure area behind it, the exhaust gases will be assisted in withdrawal from the engine. Furthermore, as motor 2 is turned, the gases will be discharged at an angle to the boat axis. See FIG. 4.

In using a marine vehicle as described above in belowfreezing weather, wherein the ambient temperature is below 32 F., ice may tend to collect on or adjacent hydrofoil 13. Since the engine exhaust gases flowing through housing l0 and passageway 18 are hot, the surrounding structure will be raised to substantially above 32 F. This will prevent or eliminate the formation of ice thereon, especially adjacent the air-water interface.

FIG. 5 illustrates how the rear hydrofoil 13 turns with the outboard motor 2 in steering of the boat and thereby the hydrofoil is maintained more nearly in alignment with the direction of movement through the water to provide better lift characteristics.

While the invention is shown as involving only one hydrofoil-equipped outboard motor, more than one could be connected to the hull transom without departing from the spirit of the invention. In some instances, a stern drive unit could be employed.

Various modes of carrying out the invention are contemplated as being within the scope of the following claim particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

In a marine vehicle having a hull; a first transversely extending hydrofoil fixedly secured to the hull forwardly of the stern thereof; an outboard propulsion unit connected to the transom of the hull and being steerable about a vertical axis disposed rearwardly of the transom; said outboard propulsion unit being driven by an internal combustion engine having an exhaust port, drive means extending through a downwardly extending underwater housing of said unit, and a propeller disposed at the lower end portion of said housing and connected to said drive means for propelling the vehicle through the water; a second hydrofoil carried by said propulsion unit housing above said propeller and adapted to lift said propulsion unit and said hull so that at least a portion of said hull is above the surface of the water with the hydrofoil and propeller remaining therebeneath, said second hydrofoil having passage means opening rearwardly thereform; and conduit means connecting said exhaust port with the hydrofoil passage means to conduct the engine exhaust products to the hydrofoil for discharge rearwardly thereof; said second hydrofoil further being normally substantially parallel to said first hydrofoil and turning with said unit during steering of the latter so that said second hydrofoil is selectively disposed angularly with respect to the first hydrofoil.

References Cited by the Examiner FOREIGN PATENTS 2,213,609 9/40 Ronning 115 18 2,597,048 5/52 Almqvistetal 114-66.5 2,705,468 4/55 Dix 114-66.5 x 2,860,594 11/58 Kiekhaefer 115 17 2,955,559 10/60 P21111161 61 al. 11466.5 2,980,047 4/61 Korganoff et al. 11466.5 3,006,307 10/61 Johnson 114 66.5 3,077,173 2/63 Lang 114-66.5 3,085,537 4/63 I'IBEtdIlCkCtfil '11466.5

FOREIGN PATENTS 549,266 10/56 Italy.

FERGUS S. MIDDLETON, Primary Examiner. 

